Wyniki wyszukiwania - Biblioteka Nauki

1

Interactions at the mould - modifying coating - molten nickel alloy interface

100%

Binczyk F. , Śleziona J. , Gradoń P. , Michalska J. , Bąk S.

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2011

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tom Vol. 11, iss. 3

5-10

EN

The study describes thermal-chemical interactions that take place in the molten nickel alloy-ceramic mould system, where the mould is either coated with a modifying coating ('blue' mould) or is not ('white' mould). The ceramic mould based on zirconium silicate was made by investment process at the WSK Rzeszów Foundry. The main component of the modifying coating was cobalt aluminate CoAl2O4 added in an amount of 10%. Thermodynamic calculations indicated the possibility of chemical reactions taking place between the chemically active nickel alloy constituents (Al, Ti, Hf, Ta and Nb) and the components of a ceramic mould and modifying coating. The result of such interactions is the risk of the formation of cracks on the surface of mould and molten metal penetration into these cracks, combined with the formation of casting defects, like burns-on, pitting, etc., as proved by extensive X-ray microanalysis. Changes of chemical composition in the surface layer of castings were also reported.

2

Ocena dostępności farmaceutycznej magnezu z tabletek o niemodyfikowanej szybkości uwalniania

100%

Ostróżka-Cieślik A. , Dolińska B. , Ryszka F.

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2015

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tom 69

166-171

EN

INTRODUCTION. Magnesium is one of the macroelements required to maintain normal body homeostasis. During studies, a positive effect in the prevention of cardiovascular disease, postmenopausal osteoporosis and diabetes was found. Unfortunately a deficiency of this element in the daily diet was observed, so supplementation is recommended. The aim of the study was to determine the influence of the kind of magnesium compound on the availability of Mg2+ with a tablet with an unmodified release rate. MATERIALS AND METHODS. The following preparations were used: Biomagnezja 150, Citromag B6 and Biomagnezja Plus (FZNP "Biochefa"). Examination of the release rate of the active substance was performed in a paddle apparatus at T = 37°C ± 0.5°C for 120 min., with a mixer at 50 revolutions/min. and using 0.1 mol/dm3 HCl (pH = 1.2). For analysis of the magnesium release, Statistica software with pharmaceutical extensions: Dissolution Profiles was used. RESULTS. Analysis of the tested products showed that the % of magnesium released increased in the following order: Biomagnezja Plus, Biomagnezja 150, Citromag B6 and was respectively 45%, 61% and 70 %. The release rate constant increased in the same order and it was respectively 0.0138 min-1, 0.0146 min-1, 0.018 min-1. CONCLUSIONS. The factors affecting the release of magnesium in vitro are the solubility of the compound, the presence of an inorganic anion or an organic ligand and the stability of the compound. A higher solubility makes a higher percentage of release. The presence of an organic ligand (hydrogen citrate) determines a greater percentage of the released dose in comparison with the magnesium oxide thereof.

PL

WSTĘP: Magnez jest jednym z makroelementów niezbędnych do zachowania prawidłowej homeostazy organizmu. Stwierdzono jego pozytywne działanie w profilaktyce chorób sercowo-naczyniowych, osteoporozy pomenopauzalnej i cukrzycy. Niestety, obserwuje się niedobory tego pierwiastka w codziennej diecie, dlatego wskazana jest jego suplementacja. Celem badań było określenie wpływu rodzaju związku magnezu na dostępność farmaceutyczną Mg2+ z tabletek o niemodyfikowanej szybkości uwalniania. MATERIAŁ I METODY: Do badań wykorzystano preparaty: Biomagnezja 150, Citromag B6 i Biomagnezja Plus (FZNP „Biochefa”). Badanie szybkości uwalniania substancji czynnej wykonano w aparacie łopatkowym w T = 37°C ± 0,5°C, w czasie 120 min, przy 50 obrotach mieszadła/min, stosując 0,1 mol/dm3 HCl (pH = 1,2). Do analizy przebiegu uwalniania zastosowano program Statistica Zestaw Farmaceutyczny: Profile Uwalniania. WYNIKI: Analiza badanych preparatów wykazała, że procent uwolnionego magnezu wzrastał w kolejności: Biomagnezja Plus, Biomagnezja 150, Citromag B6 i wynosił odpowiednio: 45%, 61% i 70%. W takiej samej kolejności rosły stałe szybkości uwalniania: 0,0138 min-1; 0,0146 min-1; 0,018 min-1. WNIOSKI: Czynnikami wpływającymi na uwalnianie magnezu w warunkach in vitro są rozpuszczalność związku, obecność nieorganicznego anionu lub organicznego liganda i trwałość związku. Im większa rozpuszczalność substancji, tym wyższy procent uwalniania. Obecność liganda organicznego (wodorocytrynianu) determinuje większy procent uwolnionej dawki magnezu w porównaniu z jego tlenkiem.

3

Strength and tribological properties of sintered powder composite materials based on copper with addition of alumina and nickel oxide

100%

Feldshtein E. , Dyachkova L.

International Journal of Applied Mechanics and Engineering

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2012

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tom Vol. 17, no. 1

41-52

EN

In the paper, the influence of oxide addition on the strength and mechanical properties of a sintered powder material based on copper is described. The increase of alumina content in the composite sintered material leads to decreasing its strength. The most significant decrease of strength is observed when less than 5% of alumina is added to the total volume. A further increase of the alumina content practically leaves the bending strength unchanged and decreases the strength limit in compression insignificantly. The addition of mixture of 80% of the alumina and 20% of the nickel oxide increases the bending strength about 40 50 MPa, and also promotes the formation of a more homogeneous and fine-grained structure, as well as decreases material porosity. The average coefficient of friction of the "sintered composite material - hardened steel C45" pair practically did not change over time. The lowest coefficients of friction were observed for a material containing alumina addition. An addition of Motor Life Professional additive to the lubricant oil reduces the coefficient of friction for the material free of oxides more than 30%. The temperature of friction is reduced by 25÷30% and the rate of linear wear decreases 1.4 to 3 times.

4

Comparison of surface laser alloying of chosen tool steel using Al2O3 and ZrO2 powder

100%

Labisz K. , Dobrzański L. A. , Jonda E. , Lelątko J.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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tom Vol. 39, nr 1

87-94

EN

Purpose: In this work there are presented the investigation results of mechanical properties and microstructure of the hot work tool steel 32CrMoV12-28 alloyed with oxide powders like aluminium oxide and zirconium oxide. The purpose of this work was also to determine the laser treatment conditions for surface hardening of the investigation alloys with appliance of transmission electron microscopy. Design/methodology/approach: The investigations were performed using optical microscopy for the microstructure determination. By mind of the transmission electron microscopy the high resolution and phase determination was possible to obtain. The morphology of the ceramic powder particles was studied as well the lattice parameters for the Fe matrix and phase identification using diffraction methods was applied. Findings: After the laser alloying of the hot work tool steel with the selected oxide powders the structure of the samples changes in a way, that there are zones detected like the remelting zone the heat influence zone where the grains are larger and not so uniform as in the metal matrix. The used oxide powders are not present after the laser treatment in the steel matrix. Research limitations/implications: The investigated steel samples were examined metallographically using optical microscope with different image techniques, SEM, TEM and analyzed using a Rockwell hardness tester, also EDS microanalysis and electron diffraction with Fourier transform was made. Practical implications: As an implication for the practice a new technology can be possible to develop, based no diode laser usage. Some other investigation should be performed in the future, but the knowledge found in this research shows an interesting investigation direction. Originality/value: The combination of TEM investigation for laser alloying of hot work tool steels makes the investigation very attractive for automotive and other heavy industries.

5

Material balance of the technological process in the new foundry of new ferronikel in DRENAS 2017

80%

Bajraktari-Gashi Z. , Halilaj B.

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2018

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tom Vol. 4, nr 1

29--35

EN

Experimental and industrial research of the technological process during the year 2017, including planning, is presented in this paper. That research was conducted in the new Foundry of new Ferronickel in Drenas, which is in the village of Cikatove, Drenas, the Republic of Kosovo. According to initial calculations, an amount of ore which would enter the process was determined, however the anticipated amount was different from the one used during the process. The same applies to fuel. Difference between the planned and the actual amount of ore used during the year 2017 resulted from the percentage of Ni in the amount of ore used in the foundry, demand for an Fe-Ni ferroalloy etc. The technological process in the foundry serves the purpose of processing ore of ironnickel with a high percentage of Ni in its composition. The material balance of the technological process in the new Foundry of new Ferronickel in Drenas, presented in this paper, is based on experimental and industrial data of the technological process acquired in the foundry. The material balance includes the technological process starting from calculation of the amount of ore and fuel, both making up the load for the rotary kiln. Additional contributors to the material balance are calculation of the amount of: fuel, which impacts the increase of temperature in rotary kilns, charge for the electric furnaces, metal and slags from the electric furnaces, metal and slags from the refining process (convertors) and mathematical calculation of the final product which is the ferroalloy of Fe-Ni. While preparing the material balance we have noticed greater acquisition of Ni than planned. The greater amount of Ni was produced by a smaller amount of ore than originally planned.

6

Composite aluminide - oxide phase powders for thermal spraying processes.

70%

Formanek B. , Hetmańczyk M. , Szymański K.

Inżynieria Materiałowa

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1998

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tom R. XIX, nr 4

1019-1022

EN

Article presents technological conception of composite powders manufacturing by the SHS method in the system of iron and titanium aluminides and aluminium and titanium oxides. High temperature synthesis parameters and the phase composition of powders were determined. The obtained powders are used for forming thermal barrier coatings.

7

Termodynamiczne i kinetyczne uwarunkowania reakcji chemicznych na powierzchni żelaza i chromu w atmosferze SO2 w wysokiej temperaturze.

70%

Gilewicz-Wolter J. , Żurek Z. , Środa S.

Inżynieria Materiałowa

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1999

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tom R. XX, nr 5

558-561

PL

W pracy przedyskutowano termodynamiczne i kinetyczne uwarunkowania tworzenia się zgorzelin tlenkowo-siarczkowych na żelazie i chromie w atmosferze SO2. Proces korozji żelaza i chromu jest bardzo złożony i można go wyjaśnić tylko w oparciu o przesłanki kinetyczne jak i termodynamiczne. Transport reagentów przez rosnącą zgorzelinę jest czynnikiem decydującym o przebiegu procesu korozji i budowie morfologicznej zgorzeliny.

EN

The oxidation of Fe and Cr in SO2 has been studied at 1073K-1273K at 100K intervals. The corrosion kinetics follows the parabolic rate law to a good approximation for iron. Only small deviation from parabolic rate law in initially stage process was observed, whereas oxidation process of chromium proceeds according linear rate law at 10 to the 5 Pa of SO2, parabolic rate law at 1173K and 1273 at 3*10 to the 4 Pa of SO2. The transport phenomena by radiotracer techniques were studied. The scales were composed of sulphide and oxide and grew by the outward diffusion of metals. Inward transport of SO2 molecules through the discontinuities in the scale was observed. The mechanism of sulphide and oxide formation was discussed on the basis of the thermodynamics and kinetics predictions.

8

Aqueous processing of SiAlON powders.

61%

Kudyba A. , Serkowski S. , Hintzen H. T. , Metselaar R.

Inżynieria Materiałowa

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1998

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tom R. XIX, nr 4

1268-1271

EN

To manipulate and understand the suspension behaviour in water of carbothermally prepared Ca-alpha-SiAlON and beta-SiAlON powders, to be processed by slip casting, different characterization methods were applied. These concerned: zeta potential, ESA, rheological sedimentation and floc size measurements. The best deflocculation was found at pH 10-11 where both investigated powders showed the lowest viscosity (below 10 MPa's), the lowest sediment volumes and the highest absolute of zeta potentials. At this pH the suspensions where considered to have the most favourable condition for this chosen process. The powders showed similar suspension behaviour (viscosity, behaviour, sedimentation behaviour, isoelectric points) suggesting similar surface characteristics probably due to resemblance of the surface due to oxidation treatment after carbothermal synthesis. Rheometry and zeta potential were found to be fast techniques providing the most useful and complete information of slip behaviour allowing a good choice of suspension parameters.

9

Wpływ wierzchnich warstw z własnościami katalitycznymi na ograniczenie emisji tlenku węgla unoszonego ze spalinami.

61%

Morel S. , Morel S.

Inżynieria Materiałowa

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1999

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tom R. XX, nr 5

424-428

PL

Scharakteryzowano ważniejsze uciążliwości ekologiczne związane z emisją CO oraz innych toksycznych gazów. Wyszczególniono metody umożliwiające ograniczenie emisji zanieczyszczeń z procesów spalania eksponując wśród nich spalanie katalityczne. Wyeksponowano zalety katalitycznych powłok natryskiwanych plazmowo (z tlenków metali przejściowych IV okresu) na ściany pieców, kotłów, rekuperatorów itp. urządzeń, które prócz intensyfikacji procesów chemicznych zwiększają ich trwałość, (ograniczają korozję i przejmują ścieranie) oraz kształtują procesy wymiany ciepła (intensyfikują wymianę ciepła bądź wytwarzają bariery termiczne). Przytoczono wyniki badań dotyczących katalitycznego oddziaływania ceramicznych powłok natryskanych plazmowo na powierzchnie ograniczające przestrzenie spalania na kształtowanie się parametrów spalin. Procesy katalitycznego dopalania realizowano w piecach rurowych spalając gaz koksowniczy, w łazienkowych nagrzewnicach wody gdzie spalano gaz ziemny oraz w modelowej komorze zakończonej przewodami spalinowymi, które były wypełnione ceramicznymi kształtkami natryskanymi katalitycznymi powłokami. Uzyskane wyniki pomiarów uzasadniają celowość stosowania powłok katalizujących procesy spalania.

EN

In the first part of the paper the researches on temperature distribution and CO and CO2 content in a pipe furnace are presented. The walls of combustion chamber were sprayed with catalytic coatings produced from cerium, manganese and copper oxides. The furnace was city gas-fired and combustion was performed at different values of excess air number. It was observed that depending on the type of the sprayed coating the increase of combustion gas temperature ranging from several to over a dozen per cent and distinct decrease of CO content in combustion gases were obtained. The values of those parameters strongly depend on excess air number which value cannot be lower than 0.9. The second part of the paper deals with the measurements of temperature distributions and CO and CO2 concentration in combustion gases flowing through pipe recuperator which surface was covered with coatings produced of the oxides. In that recuperator city gas was burned at excess air number within the range 0.8 - 1.1. The coatings, plasma sprayed on the surfaces of recuperator pipes, resulted in considerable decrease of CO concentration in combustion gases (by several times) and about 10% increase of combustion gas temperature, especially in the central part of recuperator as well as the increase of temperature of air heated in it by several per cent. Finally investigation were carried in gas furnace type PG-11 for heating water in flats and houses. The effect type of coatings for increase of temperature of heated water was determined in that stage of research. Above mentioned three stages of research allowed for the choice of the best plasma sprayed which obtained from mixture 43%CeO2+57%Al2O3.